Infinity shape coils for industrial fabrics

ABSTRACT

An industrial fabric/belt including spiral coils shaped as a symbol for infinity or a lemniscate, i.e., infinity elements, are joined to each other with a pintle. A fabric element is configured as a continuous loop to form an industrial fabric employing a plurality of infinity coil elements.

FIELD OF THE INVENTION

The present invention relates to industrial fabrics. More specifically,the present invention relates to industrial fabrics/belts assembled fromspiral elements or infinity shaped coil elements and formed into acontinuous or endless loop.

INCORPORATION BY REFERENCE

All patents, patent applications, documents and/or references referredto herein are incorporated by reference, and may be employed in thepractice of the invention.

BACKGROUND OF THE INVENTION

Industrial fabrics means endless structures in the foam of a continuousloop, and used generally in the manner of conveyor belts. As usedthroughout this disclosure, “industrial fabrics” refers to fabricsconfigured for modern papermaking machines, and engineered fabrics,which may be used in the production of nonwovens. Modern papermakingmachines employ endless fabrics/belts configured for use in the forming,pressing, and drying sections, as well as process belts such as shoepress or transfer belts, which may also be used in sections of themodern papermaking processes, such as in the pressing section.Engineered fabrics specifically refers to fabrics/belts used outside ofpapermaking, including use on preparation machinery for paper mills(i.e., pulp), or in the production of nonwovens, or fabrics used in thecorrugated box board industries, food production facilities, tanneries,and in the building products and textile industries. (See, for example,Albany International 2010 Annual Report and 10-K, Albany International,216 Airport Drive, Rochester, N.H. 03867, dated May 27, 2010.)

In the formation of industrial fabrics, the base structure or acomponent thereof may take a number of different forms. For example, thefabric may be woven endless or flat woven, and subsequently renderedinto an endless form with a seam. Industrial fabrics, as endless loops,have a specific length, measured circumferentially therearound, and aspecific width, measured transversely thereacross. In many applications,industrial fabrics must maintain a uniform thickness, or caliper, toprevent, for example, premature wear in areas where a localizedthickness is greater than in the immediate surrounding area, orobjectionable marking of a manufactured good carried thereon orcontacted thereby.

Industrial fabrics used in modern papermaking machines and in theproduction of nonwovens may have a width from about 5 feet to over 33feet, a length from about 40 feet to over 400 feet, and weigh fromapproximately 100 pounds to over 3,000 pounds, for example.

Because of their size and weight, and the configuration of theindustrial machines on which they are used, in many applications it isoften convenient to install industrial fabrics on the appropriatemachine as a flat article having lengthwise and widthwise edges, andjoining the widthwise edges with a seam, for example, to form acontinuous belt. When installed flat and formed into a continuous loopstructure on an industrial machine, such industrial fabrics may be knownas on-machine-seamable fabrics.

Seams, however, have presented problems in the function and use ofon-machine-seamable fabrics in that they may have a thickness, orcaliper, that is different from that of the industrial fabric edges theseam is joining. Variations in thickness between the seam and the fabricedges can lead to marking of the product carried on the fabric. Seamfailure may also result if the seam area has a greater thickness thanthe fabric edges as the seam is exposed to machine components andresulting abrasion or friction.

To facilitate seaming, many fabrics for industrial use have seamingloops formed on two opposite edges of the fabric to be joined. Forexample, seaming loops themselves may be formed from the warp yarns of aflat woven fabric. Seaming loops can be formed by removing weft yarns atthe ends of the fabric to free end portions of warp yarns. Loops areformed by reintroducing (re-weaving) the free end portions of the warpyarns into the fabric.

A seam is formed by bringing the two ends of the fabric together, byinterdigitating and alternating the seaming loops at the two ends of thefabric to align the openings in the loops to form a single passage, andby directing a pin, or pintle, through the passage to lock the two endsof the fabric together.

Alternatively, in one of the earliest uses of spiral link coils, aseaming spiral may be attached to the seaming loops at each of the twoends of an industrial fabric. An example of this method is shown in U.S.Pat. No. 4,896,702 to Crook in which a multilayer industrial fabric isformed. As shown, a tubular base fabric is formed, flattened to formedges at the lengthwise extremities of the fabric, and cross machinedirection (“CD”) yarns in the area of the edges are removed. A spiralcoil is attached to the seaming loops of the industrial fabric.Alternately, the seaming spirals may be connected to the seaming loopsby at least one connecting yarn. The coils of the spirals at the twoends of the industrial fabric may again then be interdigitated andjoined to one another on the machine with a pintle to form a seamusually referred to as a spiral seam.

Regardless of how the seam is formed, the construction of the seamdiffers from that of the rest of the fabric. Uniformity incharacteristics such as permeability to air or water, thickness orcaliper, and density, among others, is desirable in industrial belts. Inknown on-machine-seamable fabrics, construction of the seam area isdifferent than the construction of the rest of the fabric. Becauseuniform physical characteristics across the length and width of theindustrial fabric are usually preferred, and may be required, a seam isa critical part of a seamed fabric. If the seam itself is notstructurally and functionally nearly identical to the rest of theindustrial fabric, modification of the seam area may be necessary toobtain characteristics sufficiently similar to the main portion of theindustrial fabric for the intended application.

One well known fabric, which has a body similar to the seam is thespiral link belt disclosed in U.S. Pat. No. 4,839,213 to Gauthier, forexample. The '213 patent discloses a conveyor belt made of spiralsassembled together by inserting rods into channels formed byinterdigitating adjacent spirals. The belt includes a flat or othershaped member (known as “stuffer”) which is inserted inside the spiralsso as to completely or partially fill the spaces inside the spirals.There are certain drawbacks of using such a belt, however. For example,the belt has a relatively stiff body due to the use of stuffers withinthe spirals to achieve the desired lower air permeability. Alsoadditional expense, a separate process step to insert the stuffers, andadditional mass are drawbacks. The spiral link coils, when made fullwidth, can sometimes fail at one location and “unzip” across the CD whenthe belt is running on the machine, which can result in belt failure andsignificant damage to the paper machine components.

Another example of an industrial fabric is disclosed in U.S. Pat. No.6,918,998 to Hansen, which relates to a fabric manufactured frompreformed rings. The rings in the '998 patent are connected with MD orCD yarns, pintles or wires to form a flat fabric, whose ends are joinedto one another to form a continuous loop. The rings disclosed in thispatent are preferably manufactured from rigid materials, which make themrelatively stiff and incompressible.

Therefore, a need exists for industrial fabrics, for exampleon-machine-seamable fabrics, which are easy to manufacture and haveuniform characteristics throughout the length and width of the fabric.

SUMMARY OF THE INVENTION

Accordingly, one embodiment of the present invention is an on-machineseamable fabric/belt made from a plurality of spiral elements joinedtogether to provide uniform characteristics across the length and widthof the belt.

One embodiment of the present invention provides spiral elements whichmay be attached to each other to form an industrial fabric/belt. Alsoprovided is an endless structure formed from a plurality of spiralelements according to this invention and a method of making an endlessindustrial fabric/belt with the presently disclosed spiral elements,which can be on-machine seamable.

According to aspects of this invention, the spiral elements for use informing the industrial fabric/belt are shaped as an “infinity coil,” sonamed because an axial view of the coil resembles an infinity symbol,commonly, a figure-eight shaped curve, or mathematically a lemniscate.As such, each element has two loops, and the first loop of one elementinterdigitated with the second loop of the adjacent element to accept apintle, or pin through a passage formed by the interdigitated loops. Aplurality of these spiral elements are interdigitated and joinedtogether until the required fabric length is formed.

As used in this application, an infinity coil is a shaped coil ofmaterial which can, for example, be a monofilament, twistedmultifilament, coated or uncoated, or coated or uncoated metal wire,comprising two loops formed by the material passing alternately over andunder a pair of parallel linear coplanar support members and crossing inthe space between the support members. The support members may be, forexample, a double mandrel or a spiral link-type forming apparatus. Theloops may be substantially the same size and shape, although differingsizes and shapes are anticipated for certain applications. In forming aninfinity coil, a double mandrel is provided comprising two adjacentsupport members, generally parallel and coplanar to each other, andspaced apart from each other with a center-to-center spacingproportional to the desired center-to-center distance of the loops ofthe infinity coil. A material, for example, a polyester monofilament,passes over a first mandrel, passes through the space between the twomandrels, passing below and then around and over the top of the secondmandrel, back through the space between the mandrels and under the firstmandrel. Thus, in a complete turn, the material used to form an infinitycoil traces the basic curved shape of a lemniscate, or figure-eight, orinfinity symbol. Subsequent infinity coils turns are formed in the sameway, offset axially from the previous infinity coil turn. Coil turns canbe added until the desired number of coils is formed or the desiredaxial length, which may be proportional to the number of coils, results.

Other methods may be used to form the infinity coil as will be apparentfrom the following disclosure. One embodiment of the present inventionis an industrial fabric including a plurality of infinity coils having aCD length equivalent to the fabric width, the coils arranged such thatone of first and second loops of a first infinity coil interdigitateswith one of first and second loops of an adjacent infinity coil so as toform a single passage, a pintle extending through the passage, and oneor more infinity coils added to the first infinity coil or adjacentinfinity coil until the required MD length of the fabric is achieved.

Another embodiment of the present invention is an industrial fabric/beltincluding a plurality of infinity coil elements, each of the infinitycoil elements having a first loop and a second loop, wherein second loopof a first infinity coil element, having an open interior portion, andfirst loop of the second infinity coil element, having an open interiorportion, are interdigitated such that the open interior portions of thesecond loop of the first infinity coil element at least partially alignswith first loop of the second infinity coil element to form a passagetherethrough, and a pintle disposed in the passage formed by the alignedloops to join the first infinity coil element to the second infinitycoil element.

Yet another embodiment of the present invention is an industrial fabricincluding a plurality of coil materials formed as three or more closedcurves forming three or more adjacent coil loops, the three or more coilloops enclosing respective open interior portions, and intersectionregions between adjacent coil loops in which the coil material Ruining acoil loop intersects with material forming an adjacent coil loop.

Yet another embodiment of the present invention is a coil including atleast one infinity coil element comprising a plurality of loops, each ofthe loops having an axis parallel to and collinear with the axis of eachof the other loops of the plurality of loops, wherein, when viewedparallel to an axis of one of the plurality of loops, each of theplurality of loops forms a closed curve with a respective open interiorportion.

Yet another embodiment of the present invention is a coil including acoil axis, an axial length parallel to the coil axis, a widthperpendicular to the axial length, a continuous strand of materialformed into a continuous helical plurality of infinity coil elements,each of the plurality of infinity coil elements comprising at least afirst loop and a second loop, each of the loops having an axis parallelto and collinear with the axis of the coil, wherein, the axes of the atleast first loops are collinear with one another and the axes of thesecond loops are collinear with one another such that, when viewedparallel to the coil axis, each of the plurality of loops appears toform a closed curve with an open interior portion.

Yet another embodiment of the present invention is a coil elementincluding a coil material formed as a lemniscate having two closedcurves forming first coil loops and second coil loops, the first andsecond coil loops enclosing respective first and second open interiorportions, and an intersection region between the closed curves in whichthe coil material forming the first coil loop intersects with materialforming the second coil loop.

Yet another embodiment of the present invention is a coil elementincluding a coil material formed as three or more closed curves formingthree or more adjacent coil loops, the three or more coil loopsenclosing respective open interior portions, and intersection regionsbetween adjacent coil loops in which the coil material forming a coilloop intersects with material forming an adjacent coil loop.

It is noted that in this disclosure and particularly in the claims,terms such as “comprises,” “comprised,” “comprising” and the like canhave the meaning attributed to it in U.S. Patent law; e.g., they canmean “includes,” “included,” “including” and the like.

For a better understanding of the invention, its advantages and specificobjects obtained by its use, reference is made to the accompanyingdescriptive matter in which preferred, but non-limiting, embodiments areillustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example and notintended to limit the invention to the disclosed details, is made inconjunction with the accompanying drawings, in which like referencesdenote like or similar elements and parts, and in which:

FIG. 1 is an axial view of a conventional spiral link coil;

FIG. 1A is a perspective view of the conventional spiral link coil ofFIG. 1 ;

FIG. 2 is an axial view of the spiral link coil of FIG. 1 formed on asingle mandrel;

FIG. 3 is an axial view of conventional coils joined together by a pin;

FIG. 4 is an axial view of an infinity coil according to one embodimentof the present invention;

FIG. 4A is a perspective view of the infinity coil of FIG. 4 ;

FIG. 4B is a perspective view of a separate infinity loop according toone embodiment of the present invention;

FIG. 4C is a perspective view of a separate infinity loop according toanother embodiment of the present invention;

FIG. 5 is an axial view of the infinity coil of FIG. 4 formed on adouble mandrel;

FIG. 6 is an axial view of two infinity coils joined by a pin accordingto one embodiment of the present invention;

FIG. 7 is an axial view of the infinity coils of FIG. 6 under anincreased tensile load transverse to the axis of the fabric/belt;

FIG. 8 is a plan view of an industrial fabric/belt with pintlesinserted, according to one embodiment of the present invention; and

FIG. 9 is an axial view of the coil link fabric/belt shown in FIG. 8 ,according to one embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the invention are described below with reference to theaccompanying drawings which depict embodiments of the disclosed infinitycoil and exemplary applications thereof. However, it is to be understoodthat application of the disclosed infinity coil is not limited to thoseembodiments illustrated. Also, the invention is not limited to thedepicted embodiments and the details thereof, which are provided forpurposes of illustration and not limitation.

The present invention relates to industrial fabrics/belts, and includesengineered fabrics and fabrics used in papermaking. The presentinvention also relates to a process for producing such industrialfabrics/belts.

According to one exemplary embodiment, the fabric/belt may be a fabriccomprised of a plurality of the inventive coils or spiral elementspinned together to form a fabric.

The coils or spiral elements may be formed from a monofilament ortwisted multifilament, coated or uncoated, made from a polymer orpolymers, such as polyester, a coated or uncoated metal wire, or fromother materials known in the art. The coils may be formed as acontinuous piece having an appropriate length for the width of thefabric/belt to be formed, as measured as the cross machine direction(CD) width of the fabric/belt. In some instances, a coil formed as acontinuous piece may have the same length as, or nearly the same as, thewidth of the fabric/belt to be formed. Other coil lengths may be useful,such as lengths less then the width of the fabric/belt, or greater thanthe width of the fabric/belt and trimmed to an appropriate length. Inother embodiments, the coils may be individual pieces formed intoseparate loops, with a number of individual loops arranged across thewidth of the fabric/belt.

Coils in this application are illustrated as having two enclosedinterior portions or nodes, when viewed along the axis of the coil, forease of illustration. This corresponds with the common infinity symbolor the mathematical lemniscate. However, coils of more than two enclosedinterior portions or nodes are anticipated, and are also referred to asinfinity coils because they comprise coil turns forming at least oneinfinity symbol or lemniscate. Such coils lend themselves to similarmanufacturing techniques using a forming apparatus with a number ofsupport members corresponding to the number of desired nodes. Infinitycoils with more than two nodes have industrial uses, for example, usessimilar to those disclosed for the two-node coils.

A loop 1 for a conventional, prior art spiral coil spiral seam, as shownin an axial view in FIG. 1 and in a perspective view in FIG. 1A, has acurved shape, approximating a circular or ovular shape. Successive coilsare similarly shaped and approximately coaxial, extending into the paperas illustrated. Typically, such coils are formed by placing successivecoaxial coils of material, for example a polyester monofilament, on asingle mandrel 3 as shown in FIG. 2 . The open interior portion 2 issimilarly shaped and proportional in size to the mandrel 3 upon which itis formed. Although an ovular shaped mandrel is shown, other shapes maybe used for the mandrel.

The materials used may be a monofilament formed from one or morepolymers such as polyester. In cross section, the spiral coils may beround, rectangular, oval, flattened, or other noncircular shapes.

When, for example, two coils 1 a and 1 b are joined to opposite fabricedges (not shown) and configured to form a spiral coil seam illustratedgenerally as 5 in FIG. 3 , at least some of the open interior portions 2of the two spiral coil loops 1 align to form a passage 4 to accept apintle or pin 6, forming a seam joining the two fabric edges. The twoconventional spiral coil loops 1 are generally free to pivot or rotateabout the axis of the pintle which substantially corresponds with theaxis of the seam 5.

An entire spiral link fabric can be produced from these prior art coilsby interdigitating adjacent coils and inserting pins until the desiredfabric length is acquired as taught in U.S. Pat. No. 4,839,213, theentire contents of which is incorporated herein by reference.

When the seam 5 of FIG. 3 (or a fabric constructed entirely of theseprior art coils and pins) is placed in tension perpendicular to the axisof the seam/fabric which corresponds with the axis of the pintle 6, thatis tension in the length direction of the industrial fabric,conventional spiral coil loops 1 a and 1 b tend to elongate slightly inthe direction of the tension and contract slightly a distance in thedirection perpendicular to the tension. That is, in the case of ovalcoils, the major diameter of the coils lengthens and the minor diametershortens.

According to one embodiment of the present invention, a spiral elementis provided in the form of the infinity coil 8 in FIGS. 4 and 4A, formedas a figure-eight shaped curve, or a lemniscate, resembling a symbolcommonly used to represent infinity, co. According to one embodiment ofthe present invention, a continuous helical infinity coil as illustratedin FIGS. 4 and 4A is an infinity coil formed from a continuous strand ofmaterial. When viewed parallel to the axis X-X of the coil, thecontinuous helical infinity coil will appear to have two closed curvesforming first and second infinity coil loops 10 a and 10 b,respectively, with first and second open interior portions 2 a and 2 b,respectively. Coils according to embodiments of the invention may alsohave more than two open interior portions, yet are still referred to asinfinity coils throughout the disclosure. For example, they can havethree or more closed curves forming three or more adjacent coil loops,the three or more coil loops enclosing respective open interiorportions, and intersection regions between adjacent coil loops in whichthe coil material forming a coil loop intersects with material formingan adjacent coil loop.

The material used to form infinity coils may be any of the materialsknown in the art as suitable for industrial fabrics, for example apolyester monofilament, and may have any suitable cross section.Circular cross sectional shapes of the material may be used.Additionally, in non-limiting examples, other cross section shapes maybe used, such as oval, rectangular, square, triangular, flattened,star-shaped, grooved or other non-circular shapes may be used dependingupon particular requirements.

FIG. 4A illustrates an infinity coil 8 according to one embodiment ofthe present invention. The coil 8 comprises first and second loops 10 aand 10 b. As shown, a plurality of loops 10 a, 10 b can extend alongcoil axis X-X in the direction of coil length L. Coil 8 may have anycombination of number of loops 10 a, 10 b, and coil length Lasdetermined by the particular application.

Width W of the coil is taken perpendicular to, or generallyperpendicular to, the axis X-X and is the maximum dimension between theoutermost portion of loop 10 a and the outermost portion of adjacentloop 10 b. The width W may be the same, or substantially the same, forall adjacent loop pairs 10 a, 10 b.

Within each of the coil loops 10 a and 10 b are open interior portions 2a and 2 b, respectively. The open interior portions 2 a and 2 b haveaxes Xa and Xb, which are parallel, or generally parallel, to coil axisX. In embodiments of the inventive coils, the axis of all, orsubstantially all, first open interior portions 2 a of first loops 10 aare collinear. Similarly, in embodiments of the invention, the axis ofall, or substantially all, second open interior portions 2 b of secondloops 10 b are collinear. In some embodiments, axes X, Xa and Xb may becoplanar.

In addition to the plurality of loops 10 a and 10 b shown in FIG. 4A,embodiments of the invention include individual infinity coil elements 8a comprising at least one complete loop 10 a and one complete loop 10 bas illustrated in FIG. 4B. Individual coil elements 8 a may be formed bycutting the coil element of FIG. 4 in an appropriate location to formtwo complete loops and joining the free end portions 2 c to form theindividual coil element. Portions of the coil 8 a which cross, with oneportion of the coil crossing over the other, or intersect, between theopen interior portions 2 a and 2 b may be affixed to each other byadhesive, welding, bonding, or other known methods after formation ofthe coil 8 a. Thus, one loop 10 a and one loop 10 b are formed, eachloop forming a completely closed interior portion 2 a or 2 b,respectively, of individual coil element 8 a. Alternately, othertechniques may be employed in forming individual coil elements 8 a, asshown, in FIGS. 4B and 4C. Individual coils can be formed from molten orsoftened polymers or resins by known plastic fabrication methods. Suchmethods include, as non-limiting examples, injection molding, extrusionmolding, compression molding, transfer molding, or casting. In someembodiments, the portion of seam material 2 d may intersect on the same,or substantially the same, plane between the open interior portions 2 a,2 b of the coil 8 a as illustrated in FIG. 4C. Thus the portion of coil8 a between the open interior portions 2 a, 2 b may be integrally formedwith loops 10 a and 10 b. The individual coil elements 8 a thus formedare comprised of one loop 10 a and one loop 10 b, joined at 2 d, eachloop forming a completely closed interior portion 2 a or 2 b,respectively.

As used herein, the term “infinity coil” includes both continuoushelical infinity coils and individual infinity coil elements unless adistinction is made for clarity.

Continuous helical infinity coils 8 can be formed on a double mandrelcoil former comprising generally parallel coplanar mandrels 3 a and 3 bas shown in FIG. 5 . Infinity coils 8 can be formed, for example, bypassing material, for example, polyester monofilament, over the top of afirst mandrel 3 a, through the space between the two mandrels, below andthen around and over the top of the second mandrel 3 b, back through thespace between the mandrels and under the first mandrel 3 a. Thus thecoil forming material traces the path of a figure-eight as the infinitycoils 8 are formed around mandrels 3 a and 3 b. This pattern cancontinue with each coil turn offset axially from the previous, until thedesired number of coils, or the desired axial length of the infinitycoil 8, which may be proportional to the number of coils, is formed. Inthis manner a spiral element comprising a plurality of infinity coils 8can be formed with loops 10 a and 10 b, with each loop 10 a formingcoaxially with previous loops 10 a and each loop 10 b formed coaxiallywith previous loops 10 b.

The two individual mandrels 3 a and 3 b comprising the double mandrelare illustrated as having a round cross section for ease of illustrationonly. The mandrels may be of any suitable shape to yield the desiredshape of the infinity coil loops 10 a and 10 b. The mandrels are alsoshown as substantially the same size for ease of illustration. However,the mandrels 10 a and 10 b may be the same, or substantially the samesize, or one mandrel may be larger than the other, or differentlyshaped, as desired.

Other techniques may be employed in forming the inventive infinitycoils. For example, the infinity coil could be molded from a molten orsoftened polymer or resin as one piece using known molding methods, suchas, for example, injection molding, extrusion molding, compressionmolding, transfer molding, or casting. The material used for the coilcould also be extruded in a linear or near linear form and mechanicallydeformed into the lemniscate or infinity shape, with or without theapplication of heat. The material could also be extruded in a mannersuch that the extruded material forms the lemniscate or infinity shapeeither by moving the extruding head or by moving the bed or receptacleupon which the material is extruded.

According to one exemplary embodiment of the present invention, theindustrial fabric/belt 12 can be formed by interdigitating two infinityshaped coils formed according to the above embodiments. In forming aninfinity coil fabric/belt 12 a first infinity coil 8 a is joined with asecond infinity coil 8 b via respective loops 10 b of the infinity coils8 a and 8 b using a known method of joining, such as a pintle, asillustrated in FIG. 6 , for example. More specifically, loops 10 b fromfirst infinity coil 8 a are interdigitated with loops 10 b from secondinfinity coil 8 b such that the open interior portions 2 b of the loops10 b at least partially align and form a single passage 4 in the seam12. The passage 4 may be sized to allow a pintle or pin 6 to passthrough the aligned open interior portions 2 b of loops 10 b, joiningthe coil elements 8 a and 8 b. Similarly, a third infinity coil 8 c (notshown) is joined to the second infinity coil 8 b in the same manner inwhich 8 b is joined to 8 a, a fourth infinity coil 8 d (not shown) isjoined to the third infinity coil 8 c in the same manner in which 8 c isjoined to 8 b, and so on and so forth until the desired length of thefabric/belt is produced.

The loops 10 b from the first and second infinity coil loops 8 a and 8 bmay interdigitated and alternate, i.e., alternatingly interdigitate, oneloop from a first coil, the next loop from a second coil, followed by aloop from the first coil in a repeated pattern along the length of thefabric. However, other patterns of interdigitation may be used asrequired.

According to one embodiment of the present invention, an industrialfabric 12 may be formed using several of the disclosed infinity coilsinterdigitated with one another and joined using pintles or pins 6, asshown in FIG. 8 , for example. As illustrated in FIG. 8 , infinity coils8 a, 8 b, etc. may be joined to form fabric/belt 12 together. Morespecifically, infinity coils 8 a and 8 b may be drawn toward each othersuch that infinity loops 10 b of infinity coil 8 a may interdigitatewith loops 10 b of infinity coil 8 b and open interior space 2 b ofinfinity loops 10 b at least partially align with each other to form asingle passage (reference 4 in FIG. 6 ) as illustrated in FIG. 9 , forexample.

A pintle or pin 6 may be passed through the formed passage and throughall, or substantially all, of the infinity coil loops 10 b joininginfinity coil 8 a with infinity coil 8 b.

The industrial fabric/belt 12 as shown in FIG. 9 behaves in a mannersimilar to the coils 12 in FIGS. 6 and 7 . That is, when the industrialfabric 12 is under tension perpendicular to, or substantiallyperpendicular to, the fabric 12 in the length direction of theindustrial fabric, that is, a longitudinal tension, will be undertension and experience some thinning. The flexible (compared to stiffprior art conventional spiral link coils) infinity coils 8 a and 8 bwill decrease in thickness measured perpendicular to the longitudinaltension. The ΔC of FIG. 7 will be positive and the infinity coil loopswill move away from the surface planes of the fabric, towards theinterior of the fabric, resulting in thinning of the entire fabric.Concurrently, the length of the fabric, L1 in FIG. 6 will increase to L2of FIG. 7 . Depending upon use, for example as a dryer fabric, a thinnerfabric carries less entrained air which can cause objectionable sheetblowing in the dryer section.

An additional advantage of the present technique is that duringinstallation on an industrial machine, the last two coils on the twoparallel fabric edges which will be joined together to make the fabricinto an endless loop, the insertion of the pintle can be easier as theinterior opening is larger during installation on the machine beforerunning tension is applied than after tension is applied.

Another advantage of a fabric comprising these infinity shaped coils isthe fact that there is no large open “interior space or void” as inprior art conventional spiral link coils. Therefore, no stuffer isrequired to obtain lower fabric air permeability, thereby reducingoverall stiffness, mass, and fabric cost.

According to one embodiment of the present invention, an industrialfabric may be formed from a plurality of infinity coils 8 joined to eachother to form an infinity coil link fabric. Spiral link fabrics, such asthose disclosed in U.S. Pat. Nos. 7,575,659 to Billings and 7,360,642 toPerrin, assigned to the assignee of the present invention andincorporated by reference herein, disclose a spiral link fabriccomprised of conventional spiral coils. Billings discloses a spiral linkfabric for a papermaking machine, while Perrin discloses a spiral linkbelt for use as a conveyor belt.

In a similar fashion, the presently disclosed infinity coils can bejoined with each other, with a pintle or the like, as in forming thefabric/belt 12 of FIG. 6 . By interdigitating additional infinity coils8, and joining the additional infinity coils with pintles 6 or the likeas discussed above, and repeating the procedure, an infinity coil linkfabric 18 could be produced, a portion of which is illustrated in FIG. 9in a view taken parallel to the axis of the pintles 6. As shown, aplurality of infinity coils may be joined in the longitudinal directionuntil an infinity coil link structure or seam of suitable length isobtained. The width of the structure may be determined by the length ofthe infinity coils. In a fabric thus formed, opposite fabric edges maybe joined with a pintle to form an industrial fabric (not shown) in theform of a continuous loop.

The benefits of an infinity coil link industrial fabric 18 include athinner caliper and uniform mechanical characteristics throughout thewidth and length without the need to modify portions of the structure.Important in some applications is the uniform surface characteristicsresulting from the lack of seams with a construction different than theremaining fabric, which may cause discontinuities in the surfacecharacteristics.

According to one embodiment, industrial fabric/belt 12 can be formedusing a plurality of infinity coil elements 8 a, as shown in FIG. 4B,for example. In this embodiment, plurality of infinity coil elements 8 aare aligned next to each other in a single row such that the desiredwidth of the final fabric is achieved. Infinity loops 10 a and 10 b fromadjacent rows of such infinity coil elements 8 a are interdigitated andjoined using pintles or pins 6, as described in the above embodiments toform a fabric/belt 12 of the required length. These steps may be carriedout manually or may be carried out using a machine that is configured toalign the individual elements in rows and then interdigitate infinitycoil elements in adjacent rows in order to form the final fabric.

According to another embodiment, industrial fabric/belt 12 can be formedusing a plurality of infinity coil elements 8 a, as shown in FIG. 4C,for example. In this embodiment, plurality of infinity coil elements 8 aare aligned next to each other in a single row such that the desiredwidth of the final fabric is achieved. Infinity loops 10 a and 10 b fromadjacent rows of such infinity coil elements 8 a are interdigitated andjoined using pintles or pins 6, as described in the above embodiments toform a fabric/belt 12 of the required length. These steps may be carriedout manually or may be carried out using a machine that is configured toalign the individual elements in rows and then interdigitate infinitycoil elements in adjacent rows in order to form the final fabric.

Having thus described in detail various embodiments of the presentinvention, it is to be understood that the invention defined by theabove paragraphs is not to be limited to particular details set forth inthe above description as many apparent variations thereof are possiblewithout departing from the spirit or scope of the present invention.

The invention claimed is:
 1. A coil comprising: a plurality of infinitycoil elements comprising a first loop, a second loop, and anintersection region wherein the first loop intersects and joins with thesecond loop, each of the first loops having an axis collinear with theaxes of each of the other first loops and each of the second loopshaving an axis collinear with the axes of each of the other secondloops, the axes of the first loops being parallel to and separated fromthe axes of the second loops; wherein, when viewed parallel to an axisof the first or second loop, each of the first loops and second loopsform a closed curve with a respective open interior portion; and whereinthe coil is suitable for use in an industrial fabric and is formed frommaterial selected from the group consisting of: a monofilament, twistedmultifilaments, and metal wire.
 2. The coil of claim 1, wherein thefirst loop and second loop form at least two closed curves.
 3. A coilcomprising: a coil material formed as a lemniscate having two closedcurves forming first coil loops and second coil loops, the first andsecond coil loops enclosing respective first and second open interiorportions, and an intersection region between the closed curves in whichthe coil material forming the first coil loop intersects and joins withmaterial forming the second coil loop, axes of the first coil loopsbeing parallel to and separated from axes of the second coil loops; andwherein the coil is suitable for use in an industrial fabric and thecoil material is formed from material selected from the group consistingof: a monofilament, twisted multifilaments, and metal wire.
 4. The coilof claim 3, wherein the coil is coated.
 5. The coil of claim 3, whereinthe lemniscate is planar.
 6. A coil comprising: a coil material formedas three or more closed curves forming three or more adjacent coilloops, the three or more coil loops enclosing respective open interiorportions, and intersection regions between adjacent coil loops in whichthe coil material forming a coil loop intersects with material formingan adjacent coil loop axes of the coil loops being separated from axesof successive coil loops; and wherein the coil is suitable for use in anindustrial fabric and the coil material is formed from material selectedfrom the group consisting of: a monofilament, twisted multifilaments,and metal wire.
 7. The coil of claim 6, wherein the coil material iseither: a. molded to form the three or more adjacent coil loops, b.extruded in a substantially linear form and mechanically deformed intothe three or more adjacent coil loops, or c. extruded such that extrudedmaterial forms the three or more adjacent coil loops either by moving anextruding head or by moving a receptacle upon which the material isextruded.
 8. The coil of claim 6, wherein the coil is coated.
 9. Thecoil of claim 6, wherein the adjacent coil loops are planar.